Conventionally, the performance of a CPU (central processing unit) in an information processing apparatus such as a main frame is fixed for each product model and corresponds to the price. For this reason, with initial adoption of a main frame, the user needs to adopt a product model that corresponds to the CPU performance required for the peak of the processing amount.
However, periods in which the processing amount increases and decreases can be planned by the user, and there is a need for reducing cost by degrading the CPU performance in a period with a low utilization rate. On the other hand, there is also a need for enhancing the processing capacity by raising the CPU performance while utilizing the current machine model as much as possible when the processing amount increases.
Meanwhile, for a manufacturer offering main frames such as the applicant, there is a need to keep manufacturing cost low by manufacturing a large volume of a little variety of products, rather than manufacturing a small volume of a large variety of main frame products.
Therefore, if the CPU performance can be made variable in one unit of a main frame product, it becomes possible for the manufacturer side to offer product efficiently, by determining the CPU performance upon shipment from the factory.
For such reasons, the applicant disclosed a technique, in an information processing apparatus, comprising means to specify a performance target value, means to generate a performance control pulse according to and corresponding to the specified performance target value and order execution means to set an order execution period and an order execution suppression period alternately according to the generated performance control pulse, with which the performance of an information processing apparatus can be adjusted with a high accuracy, by matching the ratio of the pulse period to the pulse width of the performance control pulse with the performance target value by the means to generated a performance control pulse, in Japanese Laid-open Patent Publication No. 61-246840 (hereinafter, Patent Document 1).
Furthermore, in Japanese Laid-open Patent Publication No. 01-315828 (hereinafter, Patent Document 2), a technique with which conflict and the like with the operation timing of another information apparatus can be avoided by making the period of the performance control pulse adjustable was disclosed.
As another conventional art, Japanese Laid-open Patent Publication No. 2003-196083 (hereinafter, Patent Document 3) discloses a technique to suppress the power consumption and heat generation for the system as a whole in a case in which the CPU requires a wait time in relation with a device or in processing a program, by degrading the operation performance of the CPU and suppressing the power consumption.
Meanwhile, Japanese Laid-open Patent Publication No. 04-051325 (hereinafter, Patent Document 4) discloses a technique related to a method of adjusting the CPU usage time for each program.
In addition, Japanese Laid-open Patent Publication No. 2006-65430 (hereinafter, Patent Document 5) discloses a technique that makes it possible to change the CPU performance of a virtual machine and to use the virtual machine with the performance according to the user's need by changing a dummy cycle added to the order execution process according to the user's usage status of the virtual machine and the user's usage conditions of the machine.
However, with the technique disclosed in Patent Document 1, the CPU performance of the main frame is fixed upon shipment from the factory and cannot be changed afterward.
In addition, with each technique disclosed in Patent Documents 2-5, while each of them offers a technique with which the CPU performance can be adjusted, the CPU performance cannot be set easily and securely according to changes in the operation contract.
Thus, conventionally, the need of main frame users could not be satisfied sufficiently for operation change such as to reduce cost by entering a usage contract with a degraded CPU performance corresponding to a low processing amount upon adopting, and to raise the CPU performance gradually by upgrading the usage contract according to increases in the processing amount afterward.